America's 1977 International Emergency Economic Powers Act (IEEPA) lets presidents claim unusual and/or extraordinary foreign threats, declare a national emergency, and regulate commerce accordingly.
Presidents took full advantage deceptively, unjustifiably, and illegally. Targeting Iran began in November 1979. Iranian assets were lawlessly seized. A full trade embargo followed.
In January 1981, it was lifted under provisions of the Algiers Accords. Most Iranian assets were unblocked. Nonetheless, Iranian Assets Control Regulations remained in effect.
Sanctions harm nations. Ordinary people are hurt most. That's the whole idea. Iranians feel the full brunt of US ruthlessness. Multiple rounds of sanctions have been imposed. Doing so is lawless. The previous article explained.
The General Assembly's 1974 Charter of Economic Rights and Duties of States says no nation may use or encourage use of economic, political or other measures to coerce another country to to subordinate its sovereign rights in any way.